1. Field of the Invention
The present invention relates to a combination weighing and counting apparatus for selecting a combination of articles that falls within a tolerance range, by combining weights or numbers of the articles such as, for example, potato chips or candies.
2. Background Art
Conventionally, this type of combination weighing and counting apparatus is equipped with a plurality of hoppers for weighing of articles and a funnel-shaped collecting chute having a slide surface inclined towards a discharge mouth at a lower end. The articles are, after having been supplied into each of the hoppers, weighed individually and the resultant weight values are subjected to a combination calculation so that a batch of the articles which have been weighed at a time, resulting in a combination of the weights or numbers falling within a tolerance range, are discharged from the associated hoppers into the collecting chute. The articles so discharged into the collecting chute are, after having slid along the slide surface of the collecting chute towards the discharge mouth, subsequently discharged from the discharge mouth and are then packaged in a bag by a packaging machine positioned therebelow (Japanese Laid-open Patent Publication No. 8-193871).
In the meantime, for the purpose of reducing the cost, a process of packaging the articles is desired to be speeded up. However, with the above described apparatus, since the articles from the hoppers are supplied towards the discharge mouth at the lower end while sliding downwardly along the sliding surface of the collecting chute, the speeds at which the articles slide are apt to vary from one article to another because of a frictional resistance with the sliding surface. As a result thereof, the articles for one combination weighing cycle are supplied in the form as lined up towards the discharge mouth, a relatively large length of time is required up until all of the articles for one combination weighing cycle complete their travel past the discharge mouth. Thus, if a relatively large length of time is required up until the articles for one combination weighing cycle travel past the discharge mouth, the timing at which the hoppers are opened for the subsequent combination weighing cycle and the timing at which the bag is sealed by the packaging machine tend to be delayed. This frustrates speeding up of the weighing and counting operation and the packaging operation.
The present invention has for an object to provide a combination weighing and counting apparatus capable of supplying the articles for each combination weighing cycle, which has been supplied onto the collecting chute, quickly in a cluster form towards the discharge mouth without giving rise to a difference in speed, and discharging the articles in a cluster form through the discharge mouth all at once to thereby achieve a high speed weighing and counting operation.
In order to accomplish the foregoing object, the present invention is directed to a combination weighing and counting apparatus which comprises a plurality of hoppers and is operable to select a combination of articles supplied into the hoppers by combining respective weights or numbers of the articles within the corresponding hoppers so that the combination of the weights or numbers may fall within a tolerance range, wherein an upper stage chute portion of a collecting chute for collecting the articles supplied from the hoppers and discharging them from a discharge mouth at a lower end thereof has a shape and an angle of inclination, both of which are so designed that the articles supplied from the hoppers can be discharged in a cluster form and reach the discharge mouth while the discharged articles depict a parabolic line.
According to the foregoing structure, the articles for each combination weighing cycle are supplied into the upper stage chute portion of the collecting chute and then fall naturally in the cluster form towards the discharge mouth of the collecting chute while depicting the parabolic line. Because of this, the individual articles emerging outwardly from the upper stage chute portion of the collecting chute can be quickly collected in the cluster form at the discharge mouth without substantially contacting other portions of the collecting chute, that is, without being affected so much by the frictional resistance brought about by the collecting chute. Accordingly, the timing at which the hoppers are opened for the subsequent weighing cycle can be accelerated to thereby achieve a high speed weighing and counting operation.
Also, in the present invention, a partitioning member is preferably provided in a portion of the upper stage chute portion below the hoppers for preventing the articles, supplied from the hoppers, from dispersing in a direction circumferentially of the collecting chute. By so doing, even the articles such as, for example, candies, of a kind apt to jump laterally at the time they are supplied into the upper stage chute can advantageously be prevented by the partitioning members from dispersing in the direction circumferentially of the upper stage chute portion. Accordingly, the articles can arrive at the discharge mouth having traveled the shortest distance and, consequently, the articles will not line up upwardly and downwardly and are rather quickly collected in the cluster form, to thereby enable a further high speed counting and weighing operation.
Furthermore, in the present invention, the collecting chute preferably includes the upper stage chute portion and a lower stage chute portion positioned below the upper stage chute portion and of the chute portions the lower stage chute portion preferably has a plurality of inner wall surfaces arranged up and down, each of the inner wall surfaces being rectilinearly inclined at a different angle of inclination, in which case each of the inner wall surfaces has upper and lower ends in a longitudinal section positioned on the parabolic line, which defines a path for natural fall of the articles, or at respective location radially outwardly thereof. By so doing, at least the lower stage chute portion can be easily obtained by bending a plate member since the inner wall surface thereof is formed as a rectilinearly inclined surface, thereby reducing the cost of manufacture.
In one preferred embodiment of the present invention, a radially outer wall of each of the hoppers is inclined at a small angle of inclination relative to an inner bottom surface of the upper stage chute portion, and a gate for controlling supply of the articles within the respective hopper is pivotally fitted to and about a horizontally extending support shaft positioned radially inwardly of the respective hopper.
Thus, if the radially outer wall of each of the hoppers is inclined at a small angle of inclination relative to an inner bottom surface of the upper stage chute portion, the angle of collision of the articles with the upper stage chute portion can be reduced to minimize the force of collision and, therefore, the fragile articles such as, for example, potato chips can be smoothly supplied from the hoppers onto the upper stage chute portion without being damaged. Also, since the gate is pivotable about the horizontally extending support shaft positioned radially inwardly of the respective hopper, even though the outer wall of each hopper is inclined as described above, the gate can be opened large while both are positioned close to each other with no need to use a relatively large space between the respective hopper and the upper stage chute portion.
Accordingly, positioning of the hoppers and the upper stage chute portion in respective locations close to each other, the distance for the article to travel between them can be minimized to thereby minimize the speed at which the article may collide against the upper stage chute portion. For this reason, the articles from the hoppers can, while the damage thereto is suppressed, be supplied onto the upper stage chute portion, prevented from dispersing in the circumferential direction which would otherwise take place when the articles collide against the upper stage chute, and finally be supplied quickly in the cluster form towards the discharge mouth. In addition, since the articles can be guided by the hoppers shortly before being supplied into the upper stage chute portion, fall of the articles can be controlled in a desired direction.
If, while both are positioned close to each other, the gate is supported by a support axle positioned radially outwardly of the associated hopper, a tip thereof will contact the inner bottom surface of the upper stage chute portion when the gate is opened and, accordingly, the gate is unable to be opened large. In contrast thereto, when the gate is supported by the support shaft positioned radially inwardly of the respective hopper, the gate can be opened in a direction counter to the inner bottom surface of the upper stage chute portion and, accordingly, even though both are positioned close to each other, the gate can be opened large, whereby the articles from the hoppers can be supplied into the upper stage chute portion in the cluster form.
In another preferred embodiment of the present invention, each of the hoppers is provided with a gate for controlling supply of the articles within the respective hopper, and a first partitioning portion for preventing the articles from dispersing in the circumferential direction when the gate is opened is provided below a closed position of the gate so as to extend from opposite side walls of the respective hopper. In a further preferred embodiment of the present invention, the gate is provided with a second partitioning portion for preventing the articles from dispersing in the circumferential direction.
By so doing, when the articles within the hoppers are to be supplied onto the upper stage chute portion by opening the associated gates, dispersion of the articles in the circumferential direction can be suppressed by the first or second partitioning portion. Accordingly, the individual articles can be quickly supplied onto the upper stage chute portion in the cluster form.